| Desert
Spiny Lizard |
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Desert
Spiny Lizard (Sceloporus magister )
By John D. Windes, Nongame Biologist |
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 Scientific
Name:
Sceloporus magister. The Latin Scelo, meaning leg, and porus, meaning pore,
refer to femoral pores on underside of hind legs common to many lizards.
The Latin magister means teacher.
Description:
At 3.5-5.5 inches long (excluding tail), a large "spiny lizard. Called
spiny due to enlarged and pointy scales, or "bluebelly,' due to blue undersides
of many species. Blue patches, edged in black, run down sides of belly,
joining posteriorly to cover entire groin area, mixing into brown anteriorly.
Dorsal coloration dark and often flecked with metallic greens and yellows;
a dark wedge, geographically variable in color, occurs on each side of
neck in all populations. Adult males have blue throat patch. In females,
blue belly patches may be weak or absent, and if breeding, head may have
red to orange tint. |
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Habitat:
As its name implies, the desert spiny inhabits arid to semi-arid regions,
both upland and riparian. A good climber, it prefers rock piles and
trees as basking sites. It may be found from low desert to 5,000 feet
in any habitat that provides cover in the form of rock piles, crevices
in cliffs, woody debris, undercut wash banks, wood rat nests, rodent
burrows, logs, or trees. It is less common in open creosote flats or
other areas affording little cover. |
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Distribution:
Range envelopes Arizona; occurs in most of the Chihuahuan, Sonoran, Mohave,
and southern Great Basin deserts. Four subspecies in Arizona: Sonoran
in the southwest, twin-spotted in the southeast, yellow-backed in the
northwest, and orange-headed in the Four Corners area. Absent only
from higher elevations, particularly Mogollon Plateau and White Mountains. |
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Biology:
A diurnal species with a reputation for being shy, desert spiny lizards
are best located with binoculars, then approached slowly. Look for
them at the tops of rocks. Upon approach, you may notice the lizard
head-bobbing or "doing push-ups' and displaying belly patches. These
displays serve several functions, depending on who sees them. Flattened
to the substrate, or viewed from above, the lizard blends into its
surroundings. Evolutionarily, reproductive success is greater for animals
that remain hidden from predators, yet stand out when wanting to be
noticed, such as when trying to attract a mate. The push-up display
allows for otherwise hidden areas to be seen by a target audience that
may include others of the same species, similar species competing for
resources, or predators. Males, which have the most brightly colored
bellies, must defend territories against invading males, and attract
mates. Females are better served by less obvious coloration. This difference
between the sexes, termed sexual dimorphism, is analogous to antlers
on elk. A competing male seeing a displaying male may "keep its distance.'
A female may be attracted and even enticed to mate. To us, a bobbing
lizard may seem an easy target. It may be the lizard's way of saying "I
see you, don't bother.' If scared into hiding, it will likely re-emerge
shortly, allowing spectators to observe at a distance.
Breeding occurs in early summer; hatchlings appear August to September.
In warmer months, most of the day is spent basking and feeding. A generalized
feeder, the desert spiny opportunistically consumes arthropods, other lizards,
and occasionally plant material. It uses ambush, as well as active foraging
strategy. Its predators include roadrunners, hawks, snakes, and bullfrogs.
Desert spiny lizards hibernate in winter, except for brief activity on
warmest days. |
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Status:
he desert spiny lizard is not listed by the U.S. Fish and Wildlife Service
as threatened or endangered, and is not on the Arizona Game and Fish
Department's list of Wildlife of Special Concern in Arizona (AGFD in
prep.). It appears to be doing well in the state, and is common and
often locally abundant within appropriate habitats in Arizona. |
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Management
Needs:
No special land management actions are needed to conserve this common but
fascinating species. However, suburban and rural homeowners may enhance
or maintain its habitat by landscaping with native plants, rocks, and boulders,
and by keeping their house cats under control. |
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